The present invention relates to the path switching of light beams and especially the path switching of a laser beam using optics rotating on an alignment insensitive axis.
It has been common in the past to provide various types of optical beams and especially laser beams with various types of optics for controlling the beam. Such prior optics include rapidly rotating beams for Q-switching the laser as well as various means for shifting the optics and prisms in different positions for controlling the output of the beam. The present invention relates to a mechanism for switching an optical beam, such as a laser beam, between a plurality of paths and especially from one path to a second path with a mechanism which is insensitive to misalignment and to temperature extremes and severe vibrations. This is accomplished by the use of a prism which is supported in a cradle which uses a geneva mechanism for moving the prism on axis between positions and which produces a very accurate positioning using microswitches to stop the rotation of the prism in a precise position.
Prior U.S. patents which show shifting mechanisms for changing beams of a laser can be seen in the Guillet et al. U.S. Pat. No. 4,965,807, which is a laser apparatus having two different reflectors positioned on either end of a laser cavity and having supplementary resonant cavity structure having two different reflectors and means for shifting the reflectors in the resonant cavity between the first and second positions at both ends of the cavity simultaneously. A solenoid or the like is used to shift a shaft on its axis to move the reflectors from one reflector position to another. In the Viherkoski U.S. Pat. No. 4,852,115, a laser head is illustrated having a plurality of light transmitting and reflecting surfaces which are rotated at both ends of a laser cavity to thereby modify the laser cavity by the shifting of lenses between different positions. It has also been common in the past to use a geneva type mechanism in clocks before the advent of electronic clocks and watches. The present invention, on the other hand, is attempting to switch a light beam path between two or more paths which switches a crystal between positions mechanically in a manner that is insensitive to misalignment, temperature extremes, and severe vibrations.